1. Field of the Invention
The present invention relates generally to computer systems containing a power supply and a plurality of other subcomponents, and more particularly, to a method for automatically determining the total power requirement for the power supply based on the power requirements for each of the subcomponents, under a variety of operating modes and configurations.
2. Description of the Related Art
Present-day computer systems, such as desktop PCs and laptop computers, commonly have an architecture shown schematically in FIG. 1, comprising a power supply 101, processor 102 and additional subcomponents 103-105 such as RAM, hard disk drives, DVD drives, I/O ports, etc., that may be easily added or removed from the system. Some or all of these subcomponents (shown here, for example, with respect to subcomponents 103 and 104 but not 105) typically include a non-volatile memory containing vital product data (VPD) 106 and 107 relating to configuration parameters for the subcomponent. For example, a hard disk drive may contain information in the VPD memory indicating the number of cylinders, the number of heads, and the storage size of each cylinder.
Power supply 101 converts electrical energy from a source of energy (e.g., line current or a battery, not shown) into the various voltages and currents necessary to run the subcomponents of the computer system. For each subcomponent to function properly, that subcomponent must receive a required amount of power from the power supply. This amount of power may vary during the operation of the subcomponent—for example, a hard disk drive will need more power when the disk is accelerating than when it is constantly rotating or at rest. In addition, the subcomponents may operate under diverse operating modes. For example, it may be possible to select the operating speed of the processor, which usually affects the power consumed by the processor. The system may also support processors having different operating characteristics. For each of the possible operating modes of a particular subcomponent, it is usually possible to define the maximum power consumed by that subcomponent when operating in that mode, and also the average power required under normal usage. The total power required of the power supply must then be at least as great as the total of the average power requirements for each subcomponent in a particular set of operating modes.
When choosing the proper power supply for a particular computer system, it is therefore important to know the power requirements for each of the subcomponents in its various operating modes, based on a particular configuration. This information is usually obtained by observing a printed label on each subcomponent or by reference to specification manuals. Once the power requirements are known, the total power requirement may be computed, and the size of the power supply can then be chosen to equal or exceed this amount. Since at a later date, it may become necessary to modify the hardware configuration of the computer system to include additional subcomponents beyond those originally installed, and in order to avoid at that time replacing the power supply with a larger one, it is usually prudent to choose the power supply that is initially installed in the computer system to exceed the original power requirements by a sufficient margin to accommodate any future anticipated subcomponent expansion.
It should be appreciated that the subcomponents in present-day computer systems can include a large variety of operating modes and associated power requirements that can vary from one manufacturer to another and from one product series to another. For example, the amount of power used by the memory modules will depend on the technology used to fabricate the modules, the storage capacity of the modules, as a function of the selected clocking speeds. Because of the large number of parameters and circumstances controlling the power requirements for the subcomponents, keeping track of all of the power requirements for all of the subcomponents in all of their modes in a dynamic market where products change daily can be extremely difficult for the installer. Further, when subcomponents are changed or added to a computer system at a later date, it is necessary for the user to recompute the total power requirements in order to make sure that the power supply currently installed will be adequate. Determining the total power requirements may be difficult for the user to do, because the power information may be placed on labels that are currently inaccessible within the system, or are covered by other modules and therefore require disassembly of portions of the computer system, or are unavailable because the necessary specification manuals are unavailable.
Therefore, a need exists to quickly and easily determine the total power requirements of a computer system under a variety of operating modes and configurations.